Underfloor Heating Installation and Care Information

After installing the wet underfloor heating system check that the pipe connections to the underfloor heating manifold are tight.

All the underfloor heating loops need to be marked on the manifold, i.e. which loop serves which room. It is key to check that the plumber connects both the flow and the return to the underfloor heating manifold the correct way.

One of the most common underfloor heating water issues is air in the system.  Check that all the air has been flushed out correctly as detailed in our underfloor heating instructions.

For a pressure test of the water underfloor heating system, we recommend a Rothenberger pressure testing kit.  These are available to hire from specialist shops or your heating engineer will have one.  Normally the pressure test is for 6 bar.

It is very important with any underfloor heating system to check that the correct room thermostat is operating the correct actuator on the underfloor heating manifold.

The underfloor heating pump should start when any of the room thermostats are calling for heat.  Also, check that the heat source is firing when a room thermostat is calling for heat.

Set the correct temperature for the underfloor heating mixing valves as it shows in our underfloor heating manual.

Underfloor Heating – Water Temperature and Efficiency

Here at Underfloor Heating Systems Limited we have made sure we use the highest specification European underfloor heating water products.

For the best performance, we recommend that the underfloor heating system is installed in a concrete screeded solution. Our underfloor heating system can also be installed in timber suspended floors and floating floors.

The COP (Coefficient of Performance) for a heat pump will be much higher if water underfloor heating is used in a screeded concrete floor instead of a radiator system.

The efficiency of the heat pump will increase dramatically if the flow temperature is reduced for the heating system. This is why water underfloor heating systems are the best accompanying heating system for heat pumps.

The main benefit of water underfloor heating systems is that they can achieve the same comfort levels as radiators with a lower room temperature, as the heat is at floor level.

Weather compensation control systems don’t work very well in the UK when combined with water underfloor heating as the weather changes too quickly for them to react.

In a timber suspended floor the water underfloor heating system will respond as quickly as a conventional radiator heating system.

The floor surface temperature should never exceed 29 degree C for a water underfloor heating system, unless the underfloor heating loop is fitted in a bathroom.

Maximum flow temperature to a screeded floor is normally 55 degree C.  The water underfloor heating pipework must be pressure tested to 6 bar.

Underfloor Heating Insulation

There are many types of underfloor heating insulation. At Underfloor Heating Systems Ltd we recommend the use of Polyurethane insulation covered with an aluminium foil.

Polystyrene insulation is not recommended as underfloor heating insulation as this is far too soft and the underfloor heating staples (clips) will not hold the underfloor heating pipework in place.

Also, Polystyrene does not have very good insulation properties compared to Polyurethane insulation.  Polyurethane insulation is the best insulation for wet underfloor heating systems.

Well known brands of Polyurethane insulation are Celotex and Kingspan. These insulation boards reduce downward heat losses, are easy to cut, hold the underfloor heating pipework in place and are very reliable boards.

Underfloor heating insulation can be used for both a concrete (screeded) floor and for a timber, suspended floor construction. See our underfloor heating manual for further instructions.

The height of the underfloor heating insulation will vary according to the current building regulations for your particular project. This will generally be between 30mm and 100mm depending on the underfloor heating project and the current building regs. Ultimately, the more underfloor heating insulation is used, the less the downward heat losses will be.

If a liquid screed is used, the insulation boards need to be taped together and a membrane fitted on top of the underfloor heating insulation before the pipework is fitted. The insulation boards must be taped together if normal screed is used.

Underfloor Heating Cost

Underfloor heating normally starts from £400.00 + VAT for a small area, up to around £12.00 – £14.00 per m² for the supply of larger underfloor heating systems.

The cost is normally between £4.00 and £6.00 depending on the size and location of the project.  Underfloor Heating Systems Limited supply underfloor heating systems all over Europe equally, our approved wet underfloor heating installers can also fit the systems across the UK and the European mainland.

All of our water underfloor heating packs include free delivery and come with a hand sketch or CAD drawing as an optional extra. Project info is also supplied for each underfloor heating water order, with a full set of our underfloor heating instructions.

Our approved underfloor heating installers offer free site visits anywhere in the UK.

All of our wet underfloor heating products are made to the highest possible quality and are used throughout Europe and the UK.

The running cost for an underfloor heating system compared to a radiator system will be lower as the water temperature is only in the region of 40 degree C, compared to a radiator system that will be running at over 70 degree C.

As there are many underfloor heating companies in the UK, the underfloor heating cost has been reduced.  The key is to look for underfloor heating companies that has been in business for over 10 years and use high quality European products.

Underfloor Heating Systems

It is important to avoid air pockets in any screed used for water underfloor heating systems.  Air pockets in the screed will not conduct the heat and the underfloor heating system will not perform to it’s optimum performance levels.

The normal mixture of screed used for wet underfloor heating systems is 4:1 sand/cement mix. Normally 65 – 75 mm screed is used on top of the underfloor heating water system.  If a liquid screed is used then this is normally 50 mm.

Never use the underfloor heating system to dry the screed.  The screed must be allowed to dry naturally.  This could take up to 4 – 6 weeks.

Always fit a DPM (damp proof membrane).

Our underfloor heating pipe spacing is normally c/c 200 mm for our wet underfloor heating system.  The underfloor heating pipe will normally come in 200 m pipe coils. Never use more than 110 m for one underfloor heating loop.

Our underfloor heating pipe is marked every metre, so it is easy to check how much underfloor heating pipe has been used for each room.

See typical underfloor heating project information below that goes out with every underfloor heating order;

Pipe spacing approximate c/c 200 mm.  Max loop length 110 m.    Try to use all the pipework supplied, but you will always have waste.  Just make sure you have enough pipe to come back to the manifold, the pipe is marked every metre.

Loop lengths are only approximates!  Read the instructions provided before installing the system.

Layout suggested is;

GF, MANIFOLD LOCATED IN CUP’D

Eight room thermostats (3 core + earth).  9 Circuit Manifold.

LOOP LAYOUT (ONLY APPROXIMATE LOOP LENGTHS)

LOUNGE – 100 M AND 100 M – ONE ROOM THERMOSTAT

KITCHEN/UTILITY– 100 M – ONE ROOM THERMOSTAT

BED3 – 50 M – ONE ROOM THERMOSTAT

HALL – 50 M – ONE ROOM THERMOSTAT

BATH – 25 M – ONE BATHROOM THERMOSTAT

BED 1 – 60 M – ONE ROOM THERMOSTAT

EN-SUITE – 25 M – ONE BATHROOM THERMOSTAT

BED 2 – 40 M – ONE ROOM THERMOSTAT

Underfloor Heating Water

Before installing our water underfloor heating systems it is very important to read the underfloor heating instructions provided with the order.

Check that the correct screed thickness and underfloor heating insulation is fitted before fitting the underfloor heating water pipework.

It is critical to check the floor finish, as too thick carpet or wood on wood is not a good solution for any wet underfloor heating system.

If you are installing our single room underfloor heating kit, the mixer unit should be located in the room it is serving or as near the room that is possible.

The single room pack can take the heat from the main radiator circuit or it can be used with a two port valve an independent control with a 2 port valve.  Independent control is the best solution for any water underfloor heating system.

It is important to check that the boiler has enough heat output to cope with the water underfloor heating system.  Normally the boilers in the UK have plenty of extra output, or they are oversized, so this is not an issue.

It is best to install an automatic by-pass valve by the boiler.  This should be standard practice anyway as most boiler manufacturer would demand that a by-pass valve is fitted.

Copper or plastic pipework can be used to connect our single room pack to the primary flow and return of the heating system.

Underfloor Heating Water

If for some reason the flow meters on the underfloor heating flow manifold are indicating low flow rates, check the below;

- Is the underfloor heating pump set on full speed, ie number three.  Is the underfloor heating pump pumping the correct way, ie towards the underfloor heating flow manifold?  Is the flow and the return connected the correct way to the primary heating circuit?

- Check that their is no air in the underfloor heating water loops.  This is the most common problem with any wet underfloor heating system – ie air in the loops.

- What about rubbish in the underfloor heating mixer?  If the underfloor heating mixing valve is full of dirt, there will be no flow rates going into the underfloor heating loops.  The best solution is to clean the underfloor heating mixing valve.

- Has the underfloor heating loops been adjusted to the correct settings?  Call us here at Underfloor Heating Systems Ltd or see our technical manual on how to adjust the water underfloor heating loops.

If the water temperature is not correct to the underfloor heating water system, check that the system has been working for 24 hours and check that the heating source is providing enough warm water into the wet underfloor heating mixing valve.

If one of the rooms are not getting warm, then check that the correct actuator is doing the correct room thermostat for the wet underfloor heating system.

Normal flow rates to each water underfloor heating loop is approximately 2 l/min.

Wet underfloor heating

When connecting the 16 x 2 Henco multilayer pipe to the wet underfloor heating manifolds use the 16 x 2 mm Euroconus fittings.

Cut the underfloor heating pipe straight with the pipe cutter supplied with the order, fit the nut and the split ring over the underfloor heating pipework.

Use the calibration tool to re-shape the underfloor heating pipe and fit the insert into the underfloor heating pipework.  Finally connect the Henco pipework to our water underfloor heating manifolds.

It is very important that the water underfloor heating system is filled, flushed and pressure tested the correct way.  Please see our underfloor heating installation manual for guidelines. Each underfloor heating order is supplied with a full set of underfloor heating installation instructions.

Check that the boiler is working and the hot water system is operational.  All concrete floors must be dry before the underfloor heating water system is operated.

It is very important to fill and flush the flow and return pipework from the boiler to the underfloor heating system before the heating is operated.

The wet underfloor heating system will normally operated at a pressure of 1.5 bar.  The underfloor heating pump can be set to run at speed three.

If there is no flow rates to the underfloor heating loops, check that the underfloor heating Grundfos pump is working and that the actuators are open.  There could be air in the underfloor heating loops or the underfloor heating mixing valve could be blocked with rubbish.

Underfloor Heating Mixing Valve and Underfloor Heating Pump

Here at Underfloor Heating Systems Limited we use Reliance Water Controls underfloor heating mixing valves for our wet underfloor heating systems.

The underfloor heating pump is made by Grundfos.

The underfloor heating mixer is the ThermoMix mixing valve, one of the best mixing valves on the market.  The underfloor heating mixing valve can be mounted to the left on the underfloor heating manifold or to the right on the underfloor heating manifold.

The control pack that consists of the underfloor heating mixer and the underfloor heating pump can do up to 14 Kw underfloor heating output.

If the property is built to current building regulations, the underfloor heating pack could do up to 180 – 190 sqm floor area, ie 1000 m of multilayer pipe.

It is important that the pipework from the heating source to the underfloor heating mixing valve is flushed, as else there is a risk of dirt entering the underfloor heating water mixing valve and this could cause poor flow rates to the water underfloor heating manifolds.

The underfloor heating mixer can be adjusted from 35 degree C to 65 degree C.

The underfloor heating pump is a 25/60 pump, this is the same as a 15/60 pump.  The only difference is that our underfloor heating pump is black and the normal Grundfos pump on the market is red.  The reason for this is that our black underfloor heating pump is only sold to OEM’s and the red Grundfos pump is sold to merchants.